油气井固井水泥环开裂导致油气窜漏是一个世界性难题。本课题针对油气井水泥环开裂损伤的问题，通过采用高分子乳液改性水泥环的力学性能、抗渗性能、体积变形性能，来研究油气井水泥环的开裂损伤机理及抗裂措施。同时进一步研发油气井水泥环的自愈合技术，一旦油气井固井水泥环产生环隙或裂缝后，自修复机制就会自动启动，对损害的水泥环和窜流通道进行修复，以期大幅提高油气井固井水泥环的完整性、可靠性和耐久性。研发合成具有高吸油溶胀性能的聚合物乳液，加入到油井水泥中，油气井水泥环开裂后由于油气的侵入导致水泥石溶胀而实现裂缝的愈合。本项目将制备聚合物包覆的水泥粒子或环氧树脂微胶囊加入到油井水泥中，当水泥环开裂后，由于油气侵入或应力作用触发水泥粒子的二次水化或者微胶囊破裂固化，从而实现裂缝的自愈合。该项目的开展，将为油井水泥的抗裂提供重要的理论指导，并推动油井固井水泥技术的进步。

Cracking inevitably occurs in the cement annulus barrier in oil wells, due to the mechanical loads or dimensional variation caused by autogenous or drying shrinkages, temperature variation or chemical erosion etc. This project will investigate the cracking mechanism through systematically studying the improvement of the mechanical properties, shrinkage behaviors and permeability of hardened cement pastes with incorporation of polymer latexes. Self-healing technology is proposed aiming at comprehensively enhancing the integrity, reliability and durability of the cement annulus barrier in oil well. Polymer particles with high oil absorption capacity, cement particle covered by polymer coating and micro-capsule of epoxy resin will be prepared. With the addition of oil absorbent polymer particle, the cracks in cement annulus will self-recover by dimensional expansion. When polymer coated cement or the micro-capsules of epoxy resin are added in oil well cement, the force of cracking or the dissolution of polymer shell in the invading oil/gas will then trigger the secondary hydration of cement or the curing of epoxy resin. The cracks are self-healed ultimately. This project will establish the theoretical foundation of the cracking mechanism and progress the anti-cracking technology of the cement annulus barrier in oil wells.